Make critical sections safe in the presence of exceptions

We introduce the `with_lock` combinator that locks a mutex in an atomic fashion.
This ensures that exceptions thrown by signals will not leave the system in a
deadlocked state.

1 files changed, 1 insertions, 6 deletions

diff --git a/stm/workerPool.ml b/stm/workerPool.ml
index 45c92c3748..fef9300377 100644
--- a/stm/workerPool.ml
+++ b/stm/workerPool.ml
@@ -72,12 +72,7 @@ let worker_handshake slave_ic slave_oc =
     exit 1
 
 let locking { lock; pool = p } f =
-  try
-    Mutex.lock lock;
-    let x = f p in
-    Mutex.unlock lock;
-    x
-  with e -> Mutex.unlock lock; raise e
+  CThread.with_lock lock ~scope:(fun () -> f p)
 
 let rec create_worker extra pool priority id =
   let cancel = ref false in